SYSTEMATIC REVIEW article
Front. Nutr.
Sec. Nutrition and Metabolism
Intermittent Fasting Improves Metabolic Outcomes in Metabolic Syndrome: A Systematic Review and Meta-Analysis with GRADE Evaluation
Provisionally accepted
- 1Tianjin University Tianjin Hospital, Tianjin, China
- 2Arabian Gulf University, Manama, Bahrain
- 3Keele University School of Pharmacy & Bioengineering, Keele, United Kingdom
- 4Alfaisal University, Riyadh, Saudi Arabia
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Background: Previous studies showed that intermittent fasting has been the focus of scientific society and gained attention for its beneficial effects on metabolic outcomes. However, the results are inconsistent. Accordingly, this systematic review and meta-analysis aimed to evaluate the effect of fasting on glycemic control, lipid profile and inflammatory state. Methods: PubMed, Embase, Cochrane, Scopus, and Web of Science databases were used to retrieve the relevant studies published until September 2025. The quality of included studies was evaluated using Cochrane risk-of-bias (RoB 2) tool. Moreover, GRADE approach was employed to evaluate the quality of evidence. Results: Finally, ten studies with 701 individuals were included in the current meta-analysis. The combined effect of various type of fasting demonstrated a significant reducing effect on fasting blood sugar (FBS) (SMD = -0.51; 95% CI: -0.81, -0.20, P= 0.001), insulin (SMD= -0.27; 95% CI: -0.52, -0.03; P = 0.027) and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) (SMD= -0.39; 95% CI: -0.65, -0.12; P = 0.004), and HbA1c (SMD = -0.25; 95% CI: -0.49, -0.02; P= 0.034). Moreover, regimen successfully exerted its beneficial effect on low-density lipoprotein cholesterol (LDL-C) (SMD = -0.34; 95% CI: -0.53, -0.14; P= 0.001), and IL-6 (SMD = -0.30; 95% CI: -0.57, -0.03; P= 0.029) level too. The sensitivity analysis, indicated that excluding any single study had no effect on the overall effect size for FBS, BS, HOMA-IR, LDL-C, HDL-C. Moreover, the results of GRADE approach scored high quality of evidence for FBS, insulin, HOMA-IR, HbA1c, TC, LDL-C, and IL-6 which suggests robustness of the results. No evidence of publication bias was detected using Egger's and Begg's test (P>0.05). Conclusion: The findings indicated that intermittent fasting could have favorable effects on metabolic panel specifically, FBS, insulin, HOMA-IR, HbA1c, LDL-C, and IL-6 levels.
Keywords: intermittent fasting, metabolic syndrome, lipid profile, Inflammatory, Meta-analysis
Received: 14 Jul 2025; Accepted: 07 Nov 2025.
Copyright: © 2025 Song, H Almutairi, A Almutairi, Jamilian and Abu-Zaid. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Parmida Jamilian, jamilian.parm@gmail.com
Ahmed Abu-Zaid, abuzaid.ahhmed89@gmail.com
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